As March dragged on, more and more heavy guns arrived, clattering up behind their tractors in the darkness. A Tank and its crew were hidden not far from the Pioneers’ billets, and there were others farther from the line. A new infantry Division was pushed in to the line on their right. Other Divisions were said to be in readiness close behind. The sector became more and more lively, but no big attack was made. Winterbourne questioned Evans, who said it had been postponed to give the mud a chance to dry. What hopes! The Germans had excellent observation posts on Hill 91, and their aircraft were constantly over the British lines and back areas. They were perfectly aware that an attack was being prepared. Every night they shelled M——, shelled the cross-roads leading to M——, shelled any artillery positions they had spotted, shelled the wrecked village where the Pioneers were billeted. The cellars were good enough protection against shell splinters, but far too flimsy to resist a direct hit. Every day or night huge crumps were flung at them, exploding with concussions which shook the ground and made sleep impossible. In the day-time, Winterbourne sometimes crouched at his cellar-entrance and watched the explosions within his view. If one of these big shells hit a half-ruined house, almost every vestige disappeared in a cloud of black smoke and rosy brick dust. And there was gas, a good deal of gas. It was the beginning of the intensive use of gas projectiles, which later became so greatly perfected. Their experience of it began one March night on Hill 91. A smart local attack had driven the Germans out of their advance positions and carried the British line forward—at a cost—about two hundred and fifty yards on a front of eight hundred. Evans explained to Winterbourne that these local attacks were being made all along the line to deceive the Germans as to the exact position of the coming offensive. Since the Germans would have needed to be blind or lunatic not to see where the guns and troops were being massed, Winterbourne thought this an over-subtle and over-costly bit of policy. However, his not to reason why. The Pioneers—three platoons of them—under Evans, Pemberton and Hume, were to dig a new communication trench from the former British front line to their present Outpost line of hastily interlinked shell-holes. Evans told Winterbourne not to carry any tools: “I expect it’ll be rather a sticky do. The old Boche is pooping off whizz-bangs all day and night up there. And I’m hanged if I can find out exactly where our new front line is supposed to be. It’s a network of Boche trenches up there, and we don’t want to go barging into their line.”